1  /* Copyright (C) 1993-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.
      17  
      18     As a special exception, if you link the code in this file with
      19     files compiled with a GNU compiler to produce an executable,
      20     that does not cause the resulting executable to be covered by
      21     the GNU Lesser General Public License.  This exception does not
      22     however invalidate any other reasons why the executable file
      23     might be covered by the GNU Lesser General Public License.
      24     This exception applies to code released by its copyright holders
      25     in files containing the exception.  */
      26  
      27  /*
      28     Copyright (C) 1990 The Regents of the University of California.
      29     All rights reserved.
      30  
      31     Redistribution and use in source and binary forms, with or without
      32     modification, are permitted provided that the following conditions
      33     are met:
      34  
      35     1. Redistributions of source code must retain the above copyright
      36        notice, this list of conditions and the following disclaimer.
      37     2. Redistributions in binary form must reproduce the above copyright
      38        notice, this list of conditions and the following disclaimer in the
      39        documentation and/or other materials provided with the distribution.
      40     4. Neither the name of the University nor the names of its contributors
      41        may be used to endorse or promote products derived from this software
      42        without specific prior written permission.
      43  
      44     THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
      45     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      46     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      47     ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
      48     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      49     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
      50     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      51     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
      52     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
      53     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      54     SUCH DAMAGE.*/
      55  
      56  /* Modified for GNU iostream by Per Bothner 1991, 1992. */
      57  
      58  #include "libioP.h"
      59  #include <device-nrs.h>
      60  #include <sys/stat.h>
      61  #include <stdlib.h>
      62  #include <unistd.h>
      63  
      64  /* Return the result of isatty, without changing errno.  */
      65  static int
      66  local_isatty (int fd)
      67  {
      68    int save_errno = errno;
      69    int res = __isatty (fd);
      70    __set_errno (save_errno);
      71    return res;
      72  }
      73  
      74  /* Allocate a file buffer, or switch to unbuffered I/O.  Streams for
      75     TTY devices default to line buffered.  */
      76  int
      77  _IO_file_doallocate (FILE *fp)
      78  {
      79    size_t size;
      80    char *p;
      81    struct __stat64_t64 st;
      82  
      83    size = BUFSIZ;
      84    if (fp->_fileno >= 0 && __builtin_expect (_IO_SYSSTAT (fp, &st), 0) >= 0)
      85      {
      86        if (S_ISCHR (st.st_mode))
      87  	{
      88  	  /* Possibly a tty.  */
      89  	  if (
      90  #ifdef DEV_TTY_P
      91  	      DEV_TTY_P (&st) ||
      92  #endif
      93  	      local_isatty (fp->_fileno))
      94  	    fp->_flags |= _IO_LINE_BUF;
      95  	}
      96  #if defined _STATBUF_ST_BLKSIZE
      97        if (st.st_blksize > 0 && st.st_blksize < BUFSIZ)
      98  	size = st.st_blksize;
      99  #endif
     100      }
     101    p = malloc (size);
     102    if (__glibc_unlikely (p == NULL))
     103      return EOF;
     104    _IO_setb (fp, p, p + size, 1);
     105    return 1;
     106  }
     107  libc_hidden_def (_IO_file_doallocate)